Use fontSize * lineHeight for single line scroll

[scotttrinh]

Issue type:

• Feature request

Version:

Vimperator:	3.15.0 (created: 2016/10/05 01:11:26)
Firefox:	Mozilla/5.0 (Macintosh; Intel Mac OS X 10.11; rv:50.0) Gecko/20100101 Firefox/50.0

Description:

I noticed while scrolling that it does not seem to actually scroll line-by-line. I believe that's because here it seems to only scroll by the font size, but ignores line-height. Would y'all be interested in a PR?

Expected behavior:

Single line scrolling actions should scroll by a full line (font size multiplied by line height).

[timss]

That's a pretty cool idea, but certainly sounds challenging with complex websites that mix and mash multiple fontsizes, dynamic content etc.

Very positive to give it a try if you can cook something up though! :+1:

[scotttrinh]

I would imagine it's not worse than just using font-size, but I agree that we should try it out on different types of websites and see how it feels.

I think that the biggest place you'd notice this change is when scrolling document heavy things (like GitHub or blog articles), and in those cases I bet the font-size and line-height is pretty stable.